Functional properties and application potential of black soybean meal insoluble dietary fiber remodeled by ultrasound combined with ultrahigh pressure

Insoluble dietary fiber (IDF) has a variety of physiological functions, and black soybean meal, a by-product of black soybean processing, is a potential source of IDF. However, the large particle size and poor water solubility of black soybean meal IDF limit its sensory and functional properties. For this reason, in this study, black soybean meal IDF was modified by ultrasonic combined with ultrahigh-pressure (UU), and its effects on structural and functional properties were systematically investigated. The results showed that the water-holding (12.32 ± 0.62 g/g), oil-holding (9.47 ± 0.47 g/g), and swelling (5.71 ± 0.29 mL/g) properties of UU-IDF were significantly enhanced compared with unmodified, single ultrasound-modified, and UHP-modified. The composition of the modified monosaccharides changed and the particle size decreased. Fourier transform infrared spectroscopy (FTIR) analysis showed that the modification did not introduce new functional groups, and X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that the modification disrupted the crystalline regions and changed the thermal stability. In addition, UU-IDF showed superior performance in terms of cholesterol (9.69 ± 0.39 mg/g) and glucose (0.979 mmoL/g) adsorption capacity. The combined ultrasonic and ultrahigh-pressure treatment significantly enhanced the functional properties of black soybean meal insoluble dietary fiber (IDF), opening up new possibilities for its application in health products and functional foods.